Identical springs of steel and copper are equally stretched. On which more work will have to be done?

Identical springs of steel and copper are equally stretched. On which

1.	Identical springs of steel and copper are equally stretched. On which more work will have to be done?
Answer» Solution :Work done in STRETCHING a spring, `W=1/2 F xx DELTAL` where `Delta l` increases in length DUE to applying force, ` therefore W prop Delta l[ because (1)/(2) , F` CONSTANT] `therefore W prop (l)/(Y) [ because Delta l = (Fl )/(AY), F, l, A` are constant] `therefore (W_("steel "))/(W_("copper")) = (Y _("copper "))/( Y _(steel"))` but ` Y _("steel " ) lt W _("copper")` `therefore ` Hence, more work will be done in CASE in spring made of copper.